In many parts of the country home swimming pools are very popular. A home pool can provide a place of exercise, entertainment and relaxation for the user. One of the drawbacks of owning a pool is the need to keep it clean. Although a pool filter removes contaminants suspended in the water, a film of dirt forms on the bottom and sides of the pool and leaves and other debris collect along the bottom. It is necessary to periodically clean the pool surfaces to remove the surface film and the bottom debris.
Manual pool cleaners typically are based upon a suction principle and are connected to the pool skimmer inlet. However, these manual systems require that the user spend a significant amount of time each week cleaning the pool. Thus, automated systems for pool cleaning have been developed.
One type of automated system, which can be termed a water jet system, uses a buoyant power head connected to a high-pressure water source. One such pool cleaner, disclosed in U.S. Pat. No. 3,291,145 to Arneson, includes a pair of flexible hoses extending downwardly from the buoyant power head. The hoses have nozzles through which high-pressure water streams are ejected. As the buoyant power head moves about the surface of the pool, the cleaner hoses sweep the dirt film from the bottom and sides of the pool and the debris on the bottom of the pool towards the main drain at the pool's lower end. Waterlogged leaves and large debris, collected in one place, can then be removed from the pool. Floating leaves and other material are driven to the edge of the pool where they are removed by the pool skimmer.
Although this type of pool cleaner does a fine job cleaning the pool, a currently available pool cleaner of this type requires that water be delivered to the buoyant power head at about 50 p.s.i. However, the maximum water pressure developed by conventional pool filter pumps is about 20-25 p.s.i. Therefore a booster pump is required to use this type of pool cleaner. The need for two pumps increases the purchase and installation costs of the pool cleaner. Operating two pumps is necessarily less efficient than operating a single pump.
A second type of automatic pool cleaner uses a suction principle. These pool cleaners are typically connected to the skimmer inlet so that no booster pump is needed. Operating this type of pool cleaner does create an additional resistance to flow requiring the filter pump to work harder, and use more energy, compared to the amount it would use without the pool cleaner. One type has a suction head which attaches itself to the bottom and sides of the pool and moves about the pool in little steps. As it does so it sucks up the dirt along the pool surface. Although this type eliminates the need for a separate booster pump, it suffers from the same disadvantage common to most suction-type pool cleaners. That is, all the dirt, waterlogged leaves and other debris removed by the pool cleaner is sucked into the pool filter. This causes the filter to clog up faster so that the filter must be backwashed more often. This is a particular disadvantage when a lot of leaves or other debris collect in the pool. Therefore, if a suction type of pool filter is left unattended for a sufficiently long period, such as can occur during a vacation, the filter may well become so filled with dirt that it becomes ineffective.